Senator Ron Wyden, of the Senate intelligence committee member discusses the NSA on NBC's Meet the Press. Photograph: Handout/Reuters

Ron Wyden, the senator who is a leading voice in attempts to rein in the National Security Agency, has urged President Barack Obama to order an immediate halt to the bulk collection of domestic telephone metadata records.

The Oregon Democrat, who is a member of the Senate intelligence committee, said on Sunday the president should end the practice “right away”, rather than wait for Congress to pass legislation. The president's proposals were outlined this week; two reform bills are currently with Congress.

Wyden, a longtime critic of bulk surveillance, cautiously endorsed Obama's proposal to have such records remain with telephone companies rather than intelligence agencies, but said reform should not wait for a new law.

“I believe the president ought to make the transition right away,” he told NBC's Meet the Press. “I believe strongly we ought to ban all dragnet surveillance on law-abiding Americans, not just phone records but also medical records, purchases and others.”

Under Obama's plan, the government could obtain telephone records only if it got individual orders for individual numbers from the foreign intelligence surveillance court, also known as the Fisa court.

Wyden spoke a day after the publication of fresh reports about NSA spying on Angela Merkel, the German chancellor, based on documents supplied to media outlets by the former NSA contractor Edward Snowden.

The German magazine Der Spiegel said the NSA kept more than 300 reports on Merkel in a special databank concerning heads of state, including the leaders of Peru, Somalia, Guatemala, Colombia and Belarus.

Wyden's demand for immediate action contrasted with the views of Dianne Feinstein, chair of the Senate intelligence committee, who said Congress should debate the president's bill when it comes.

Feinstein, an outspoken defender of the NSA, also hinted that the embattled agency may be a better safeguard of privacy than phone companies.

“If this [data] is held by a large number of telecoms, with their people doing the actual querying, is privacy as closely controlled as it is with 22 vetted people at the NSA, who are supervised and watched with everything they do?” she asked, on CNN's State of the Union.

The California Democrat welcomed Obama's suggestion that the Fisa court approve every request for phone records – with the caveat that security not be compromised. “I happen to support that,” she said, “if it can be done on an urgent basis because time is of the essence, then that will be helpful.”

Two former intelligence chiefs also welcomed Capitol Hill's apparent move towards a compromise between the president's proposals and a similar House bill.

“There's a powerful convergence,” Michael Hayden, a former head of the CIA and the NSA, told CBS's Face the Nation.

Hayden suggested change was needed not because of abuse but because of the “potential for abuse” and approvingly noted that the House bill left the NSA wide leeway.

“It actually talks about all communications,” he said. “So in this sense, the NSA is able to query not just phone data, but digital and email metadata too. So I think we've arrived at a solution that actually makes people more safe, that gives people higher comfort that the government would not potentially abuse its power.”

Hayden said the intelligence community was concerned with the constitution's guarantee of reasonable expectation of privacy, and added: “Now that definition of 'reasonable' is shifting, and that makes this issue very hard.”

On the same programme Michael Morrell, a former deputy CIA director and a member of Obama's NSA surveillance review group, said the reform proposals from the president and the House should ease people's fears.

“There is a difference between the government holding the data, which creates the possibility of abuse, and the government not holding it,” he said. “The phone companies have held this data all along, so there's no additional risk.”

No one appeared keen to talk about the whistleblower who ignited the debate and found exile in Russia. Asked if Snowden should be tried, Wyden declined to comment, saying he was not a prosecutor.

General Keith Alexander did not mention the former contractor in a retirement speech on Friday, which marked the end of his directorship of the NSA and Cyber Command. A similar silence was maintained by Feinstein, Hayden and Morrell.